/images/htsTriax_button.jpg/images/Copy_of_HTS-Feature_page_01.gifHTS Triax®hts.htmSouthwire Company is a world leader in HTS cable technology with advanced designs and multiple projects placed in service with successful operations.
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HTS Triax®

HTS Triax Superconducting Cable: More Power to More People

HTS Triax® Superconducting Cable is Southwire's unique and proprietary cable design. The Triax cable locates the three electrical phases and neutral conductor concentrically on a single core. This design drastically reduces material usage and cooling requirements of the system, and therefore cost. The Triax cable has been in service at AEP in Columbus, OH since August 2006. Applications for this advanced technology address right of way and substation congestion constraints in many of today's urban environments.

HTS Triax® Superconducting Cable System
HTS cables incorporate new superconducting materials to replace the copper or aluminum conductors in conventional cables. These materials have the advantage of up to 10x increase in power density versus copper. This results in cables delivering up to 500% more Ampacity through a given underground conduit.
The Triax cable design is unique in that it places the three electrical phases concentric on a common core - something that is impossible to do with conventional transmission and distribution cables. The advantages to this design include reduced superconducting material usage and reduced cryogenic operating costs.

Reduced Material Usage
The Triax design uses approximately one half the superconducting wire as comparable single-phase cable cores. Single-phase cable cores require HTS wires to be used for the inner phase conductor as well as the outer concentric neutral for each phase. Placing the 3 electrical phases centrically in the Triaxial arrangement allows the electric fields, which are 120 electrical degrees apart, to self-cancel. This feature eliminates the need for using superconducting materials in the cable's concentric neutral conductor and therefore reducing HTS material consumption by one half.

Reduced Operating Costs
The compact Triax cable has a reduced diameter and therefore cold surface area compared to single phase cable designs. This feature reduces the cryogenic cooling requirements due to reduced heatleak into the overall system. Reducing the cryogenic load allows for a smaller refrigeration system, addressing both the upfront capital cost associated with installation as well as the ongoing operating cost of running the cooling system.

HTS cable systems consist of a flexible cable, flexible thermal insulation (cryostat), termination and joint accessories and cooling system. The cables are made on reel-to-reel processes in conventional cable manufacturing plants. They are delivered to job sites on drums just as conventional cables.

Cryogenic cooling systems are designed and built to meet the demanding reliability requirements of the electric utility industry. These systems are required to maintain the operating conditions of the HTS materials at temperatures of approximately -200°C (-320°F).

Applications and benefits of HTS cable technology include reduction in substation footprint requirements, achieving higher power throughput in congested rights of way, retrofitting existing duct banks, and high load connections between distribution substations or to high capacity users.

For additional detail on HTS cable technology, the Triax design, applications and project history, visit http://www.htstriax.com